Microlithography is used for the production of microstructured components such as for example integrated circuits or LCDs. The microlithography process is typically carried out in what is commonly referred to as a projection exposure apparatus having an illumination system and a projection objective. The image of a mask illuminated by the illumination system (=reticle) is in that case projected by the projection objective on to a substrate (for example a silicon wafer) which is coated with a light-sensitive layer (photoresist) and arranged in the image plane of the projection objective in order to transfer the mask structure on to the light-sensitive coating on the substrate.